Cartridge fuse



Dec. 28, 1923. 1,478,109

E. H. ELLISON CARTRIDGE FUSE Filed April 27 1920 Patented Dec. 18, 1923.

v 1,478,109 PATENT OFFICE.

EDWARD H. ELLISON, OF JAIIBTOWN, NEW YORK, ASSIGNOB TO KONABCH REFILL-AJBLE FUSE 00., OF JAIESTOWN, NEW YORK, A CORPORATION 01 NEW YORK.

CARTRIDGE FUSE.

Applicatlon flled April 27, 1880. Serial Io. 876,982.

To all whom itma l concern:

Be it known that I, EDWARD H. ELLISON, a citizen of the United States,residing at Jamestown, in the county of Chautauqua, State of New York,have invented certain new and useful Improvements in Cartridge Fuses, ofwhich the followin is a description, reference being had to theaccompanying drawing and to the figures of reference marked thereon.

Prior to my invention,'fuses of the ferrule or cartridge type have beenformed wherein the ends of the fusible link extend through slots in endwashers and are clamped against said washers by caps which are threadedonto the casing forming the body portion of the fuse, and said end capsare formed with openings for exposing to view a character indicating thecapacity of the fuse. No means, however, was provided for locating thiscapacity identifying character relative to the opening of the end cap,and, as a consequence, great care is necessary in the assembling of theparts in order to position the character so that it may be within thelimits of the opening in the end )ne of the objects of the presentinvention is to provide a ferrule or cartridge type of fuse of the abovecharacter with means whereby, when said fusible link is assembled, theoverlap of the bent-over portion will always be to a predeterminedamount, thus insuring that the character indicating the capacity of thefuse will be correctly placed relative to the opening in the end cap.

A further object of the invention is to provide a ferrule or cartridgetype of fuse of the above character wherein the end cap is providedinteriorly with a thread adapted to engage an exterior thread on asleeve attached to the casing or body portion, and wherein said end capis provided with an integral skirt extending down over said sleeve so asto form a uniform cylindrical contact surface of sufiicient length forengagement with the supporting clips for the fuse without restrictingthe length of the casing of insulating material.

A further object of this invention resides in providing a cartridge fuseof the above character with a fusible link, the ends of which arecomposed of a metal of a relatively high melting point and providedobvious and will in with an intermediate portion or portions of flamesas they pass outwardly through the apertures in the end caps.

- These .and other objects will in part be art be hereinafter more fullydisclosed in t e accompanying draw- 1ngs which show by way ofillustration one embodiment of the present invention.

Referring more particularly to the accompanymg drawings Figure 1 is asectional side viewof the improved fuse,

Fig. 2 is a detailed group perspective of the component part of thelink,

Fig. 3 is an end view of the link fold, the caslng being shown insection, and

Fig. 4 is a view of the link.

The invention in one of its broad aspects isdirected to a fuse of theferrule or cartridge type having a casing of insulating material,preferably tubular or cylindrical, to which are secured end caps, andassociated with each end cap is a clamping washer having a slot throughwhich the end of the fusible link extends, the end of the link beingbent over onto the washer and clamped thereagainst by the end ca and theend cap having an opening ormed therein whereby a character impressed inthe end of the link and indicating the capacity of the fuse may beviewed. The fusible link is provided with means which determine theextent to which the end of the link is bent down onto the washer. In thepreferred form of the invention, said link is formed with shoulderswhich engage against the inner face of the washer adjacent the ends ofthe slot, and this determines the extent to which'the end of the linkprojects beyond the outer face of the washer and, as a consequence, theextent to which the end of the link is to be bent down onto the washer.This insures that the indentifying character impressed in the end of thelink and indicating the capacity of the fuse will be brought intoregister with the opening of the end cap. Then agaln, the invention inanother of its broad aspects is directed to the construction of the endcap which is interiorly threaded so as to make engagement with the metalsleeve attached to the casing of insulating ma terial. This cap isformed with a skirt which extends down over the sleeve, and thus the capis formed with a contact surface of the proper length for engaging theclips in which the fuse is placed and, at the same time, the body ofinsulating material forming the casing extends substantially from oneend cap to "the other. In other words, the sleeve which is connected tothe casing and to the end cap extends almost wholly within the end cap.

Still another broad phase of the invention resides in the combination ofa link of metal of relatively high melting point and having at least oneintermediate portion of metal fusing at relatively low melting pointwith an inclosing insulation tube provided at each end with slottedwashers through which the link ends e):- tend, the same being held inposition folded over the outer faces of these washers of the end caps,closing the end of the casing and making electrical connection with thelink ends.

Referring particularly to the drawings, the invention includes aninclosing casing in the form of a tube of insulation 1 threadedinternally at each end to receive therein the metal ferrules 2 whichproject slightly beyond the end of the casing where they are enlargedradially as at 3 to provide circumferential threaded faces flush withthe outer circumference of the tube 1. Preferably the casing andferrules are held in such threaded relation by means of metal rivets 4.

Arranged at each end of the casing and abutting the end faces of thesemetal ferrules are washers 6 and 7 slotted in any desired manner, butpreferably as shown clearly at 8 in Figure 2, to provide a passagetherethrough for the ends 9 and 10 of the fusible link 1. These linkends which pass through the slots in the washers are folded over theouter faces of the washers and make electrical connection with the endcaps 11 and 12. These caps are provided with internal threads 13engaging the metal ferrules 2 and extensions or skirts 15 and 16 of thesame outer diameter as the caps, projecting inwardly over the fiber endsof the casing 1 substantially flush with the inwardly projecting ends ofthe inner metal ferrules 2, whereby an extended surface is provided foraffording good electrical contact with the usual clip.

In order to insure that the amperage mark which is stamped or otherwisemarked on the outer face of the folded over end of the link may alwaysregister with suitable apertures 18 and 19 in the end or outer faces ofthe end caps 11 the link ends are provided net/arcs with means forassuring that a uniform length of fuse will project through the washerslots 8 and be folded over the outer face of the washer. One form ofsaid means consists in providing the link ends with shoulders 20 adaptedto engage the inner faces of these washers for limiting such projection.Tn other words, when the fuse is inserted in the slot in the washer andthe fuse pulled, so that the shoulder 20 bears against the inner face ofthe Washer, a predetermined length will always be turned down over theend of the washer, bringing the number imprinted upon the end of thewasher to indicate the capacity of the fuse, directly into register withthe opening or aperture in the cap My improved fuse link has specialapplication to a fuse of the above construction due to the fact thatwhen the link metal volatilizes the gases and flames rush endwise andseek to escape through the openings 18 and 19 in the cap ends. If thelink be of the usual type, the immense heat created will tend tovolatilizeall the link metal in the path of the escaping gases so thatthe link terminals will be fused to the end washers 6 and 7. By makingmy link 5 of a metal f relatively high melting point and providing thesame intermediate its ends with a fusible portion or portions ofrelatively low melting point, the fusing is confined to the intermediateportion of the link and the terminal connections preserved.

This improved fuse link which is the subject of a co-pending applicationi. e. Serial Number 376,933, filed by applicant April 27, 1920, filedconcurrently with this application, is composed of copper intermediatethe ends of which is located a melting zone made of a series of zinesand copper sections connected together and to the copper ends of thelink proper by interfolding the metal of the successive portions.Preferably the sections adjoining the copper link ends are composed ofzinc, while arranged between these two zinc sections is a single coppersection; As a result of this arrangement, the zinc sections willvolatilize first and the intermediate copper section will drop outthereby preventing arcing. Furthermore, these adjacent portions being ofcopper, which has a higher melting point will not be fused.

Considering the fuse as a whole, it is evident that the. end ferrulesprovide a firm metallic end face for the abutting washers so that a goodelectrical connection may be had between the end caps and the linkterminals. As heretofore made, these end caps were generally threadeddirectly upon the insulation casing itself, which threads afterconsiderable use, were apt to Wear, in the present construction, byreason of the metallic threads on the outer surfaces of theend ferrules,a most durable threaded connection with the end caps is provided. Itwill also be apparent that by arranging ferrules within the bore of thecasing, when the latter shrinks, it tends to tighten the joint be tweenthe casin and the ferrule. Furthermore, by threading the metal end capsover the casing end ferrules and providing such caps with skirtsextending over the inner ends of the insulation tube to partssubstantially flush with the inner ends of said ferrules, an extendedcontact surface for the clips is provided substantially equal to thefull length of these metal ferrules.

It will be obvious that minor changes in the details of construction andarrangement of parts may be made without departin from the spirit of theinvention, as set fort in the appended claim.

Having thus described the invention, what I claim as new and desire tosecure by, Letters-Patent, is

A cartridge fuse comprising an enclosing tube of insulating material, afuse link therein having end portions of less width than the main bodyof the link to form shoulders vspaced from each end-of the link, awasher abutting and closing each end of said casing and provided with aclosed slot of width substantially equal to the width of the narrow endof the link, said fusible link extending through said tube and saidshoulders abutting the washers, the narrower ends of the link extendingthrough the slots in the washers, and the end of said link being foldedover the outer faces of the washers and provided with a fuse amperagemark thereon, and apertured metal caps closing the ends of said casinand forming an electrical connection with t e folded ends of said link,the aperture of said caps registerin with the indicating marks on saidink en In testimony whereof I afiix my signature.

EDWARD H. ELLISON.

